Follicle-stimulating hormone (FSH) is an endogenous glycoprotein hormone produced by the anterior pituitary gland. It belongs to the chemical class of pituitary and trophic hormones and is crucial for reproductive processes. FSH is also available in synthetic forms such as Gonal-F and Follistim, which are used in clinical settings. Researchers have observed that FSH plays a significant role in mammalian reproduction by binding to its receptor, FSHR, which is expressed in the gonads and various extragonadal tissues. The primary physiological roles of FSH include the regulation of reproductive processes such as follicular development in ovaries and spermatogenesis in testes. Recent research has expanded its known functions to include roles in metabolic processes, such as glucose-stimulated insulin secretion in pancreatic islets, and potential implications in conditions like polycystic ovary syndrome (PCOS) and postmenopausal diabetes. The mechanism of action of FSH involves binding to the FSH receptor (FSHR), a G protein-coupled receptor, which activates pathways such as the cAMP/protein kinase A (PKA) and calcium pathways. This activation leads to various cellular responses, including gene expression changes, proliferation, differentiation, or apoptosis, depending on the physiological context. Pharmacokinetic properties of FSH include a circulating half-life that is subject to variation depending on the specific form and route of administration. Synthetic forms of FSH are used clinically to treat infertility and are regulated by health authorities worldwide. Researchers have found that FSH is approved for use in assisted reproductive technologies, and its regulatory standing varies by country.